diff --git a/src/main/java/org/codelibs/fess/app/web/cache/CacheForm.java b/src/main/java/org/codelibs/fess/app/web/cache/CacheForm.java
index 28d0b569c..491987b67 100644
--- a/src/main/java/org/codelibs/fess/app/web/cache/CacheForm.java
+++ b/src/main/java/org/codelibs/fess/app/web/cache/CacheForm.java
@@ -16,6 +16,8 @@
 package org.codelibs.fess.app.web.cache;
 
 import java.io.Serializable;
+import java.util.HashMap;
+import java.util.Map;
 
 import javax.validation.constraints.Size;
 
@@ -40,4 +42,5 @@ public class CacheForm implements Serializable {
 
     public String lang;
 
+    public Map<String, String[]> fields = new HashMap<>();
 }
diff --git a/src/main/java/org/codelibs/fess/app/web/go/GoForm.java b/src/main/java/org/codelibs/fess/app/web/go/GoForm.java
index 3aa8a8064..42fdc8e3b 100644
--- a/src/main/java/org/codelibs/fess/app/web/go/GoForm.java
+++ b/src/main/java/org/codelibs/fess/app/web/go/GoForm.java
@@ -15,6 +15,9 @@
  */
 package org.codelibs.fess.app.web.go;
 
+import java.util.HashMap;
+import java.util.Map;
+
 import javax.validation.constraints.Size;
 
 import org.lastaflute.web.validation.Required;
@@ -44,4 +47,6 @@ public class GoForm {
     public String sort;
 
     public String lang;
+
+    public Map<String, String[]> fields = new HashMap<>();
 }
diff --git a/src/main/java/org/codelibs/fess/app/web/screenshot/ScreenshotForm.java b/src/main/java/org/codelibs/fess/app/web/screenshot/ScreenshotForm.java
index 4b481f0af..7ebc06dd1 100644
--- a/src/main/java/org/codelibs/fess/app/web/screenshot/ScreenshotForm.java
+++ b/src/main/java/org/codelibs/fess/app/web/screenshot/ScreenshotForm.java
@@ -16,6 +16,8 @@
 package org.codelibs.fess.app.web.screenshot;
 
 import java.io.Serializable;
+import java.util.HashMap;
+import java.util.Map;
 
 import javax.validation.constraints.Size;
 
@@ -41,4 +43,5 @@ public class ScreenshotForm implements Serializable {
 
     public String lang;
 
+    public Map<String, String[]> fields = new HashMap<>();
 }